When making a cake or pie, if a recipe calls for, say, 6 tablespoons of butter, using salted v unsalted would be the difference of, say, 450 mg. That's about 1/3 of a Tablespoon. Is that enough to make a difference in the outcome of a baking recipe?

That may have been true at some time in the past, but not with modern refrigeration. The salted butter and unsalted butter that appear side by side in the grocery cooler have, in all likelihood, the same history and shelf life (I get mine from TJs). I suppose you could check that by looking for a pull date.

As a side note on butter freshness - natural buttermilk was the liquid left over from butter making, and often was sour because that cream had been sitting around for a day or two till the farmer had enough to churn. But since Americans now want 'sweet cream' butter, most buttermilk is cultured skim milk, not a sour byproduct of butter making.

I suspect that many recipes that call for 'unsalted butter' date from a time when chefs and cookbook authors believed that unsalted butter was fresher or better. 20 years ago the unsalted butter may have been better, not because is was fresher or that salt was a preservative, but because only a few companies like Land of Lakes made unsalted. Everyone else, including regional dairies, just sold the salted butter that consumers wanted. Now it is easier to find unsalted side by side with salted.

Calling for 'unsalted butter' is a bit like specifying 'kosher salt'. It makes the recipe appear more modern and sophisticated, something that a chef would make, as opposed to a Better Homes and Gardens housewife.

<Calling for 'unsalted butter' is a bit like specifying 'kosher salt'. It makes the recipe appear more modern and sophisticated, something that a chef would make, as opposed to a Better Homes and Gardens housewife.>

And you know that how?

That is not true. In some recipes, it really doesn't matter whether the butter is salted or not. In others, it does matter. Most recipe writers specify unsalted butter for the reason previously stated: the cook can control the amount of salt in the recipe. There are no specs on how much salt is in the various brands of "salted butter."

From a google search for 'how much salt in salted butter' I get this explanationhttp://www.ochef.com/553.htmwith a rough maximum of 3%, 3/4t salt per stick (is that 3/4t table salt or kosher?). At 8 T per stick, that is 3/32t per tablespoon (roughly a pinch of kosher?).

On the issue of freshness it raises the point that the turn over of regular salted butter might be a lot higher than that of specialty butters.

Is there much evidence in recipes that authors and test kitchen were taking into account the amount salt in salted butter (or lack of salt in unsalted). About the best comparison I could make was for a 'white cake' in an old Joy of Cooking v the 1997 edition. Basically the same ingredients, including 1/2t salt, but unsalted butter is specified in the new edition.

It could also be that in the past, the option wasn't available and someone these days might not know which to use. When specified, it's what was used in the test kitchen. I think of it more like unsifted or sifted flour.

Actually, specifying Kosher salt is very important, as it is radically different from table salt if you measure by volume. It is not an affectation at all and is the reason many recipes fail, when people ignore this.

"Calling for 'unsalted butter' is a bit like specifying 'kosher salt'. It makes the recipe appear more modern and sophisticated, something that a chef would make, as opposed to a Better Homes and Gardens housewife."

Not necessarily. Salted butter can contain up to 3/4 tsp salt so if you're using two sticks, you do need to cut back on the amount of salt. Since the amount of salt is variable, it's easier to call for unsalted and the amount of salt and let the cook decide how much to adjust if he/she is using salted butter. It's just more exact, not sophisticated..